There are indications that television receivers which can display stereoscopic images (3D images) will be widespread and digital cameras (stereoscopic imaging apparatuses) which can take stereoscopic images of subjects will be also widespread. When a stereoscopic image obtained from images taken by such a stereoscopic imaging apparatus is displayed on a display portion of the stereoscopic imaging apparatus, an external display device (such as a large-screen television set), etc., a part of the displayed stereoscopic image may be enlarged and displayed in some cases.
There has been known a method for enlarging and displaying a stereoscopic image 92 within a display area 91 on the whole of a display surface of a display device when a user designates the display area 91 as a part of a stereoscopic image 90 in the state in which the stereoscopic image 90 has been displayed on the whole of the display surface of the display device, for example, as shown in FIG. 13.
As shown in FIG. 13, a subject 92R and a subject 92L generating a parallax amount d1 therebetween are contained in the stereoscopic image 92.
When the user moves the display area 91 to a position designated by the broken line in FIG. 13, a stereoscopic image 93 within the display area 91 after the movement is enlarged and displayed on the whole of the display surface of the display device.
As shown in FIG. 13, a subject 93R and a subject 93L generating a parallax amount d2 therebetween are contained in the stereoscopic image 93.
Here, when there is a large difference between the parallax amount d1 and the parallax amount d2, the parallax of the stereoscopic image displayed on the display device changes suddenly between before and after the movement of the display area 91. When the parallax changes suddenly thus, a sense of fatigue is given to the user viewing the image stereoscopically.
FIG. 13 will be described on the assumption that the size of the stereoscopic image 90 is the same as the display size of the display device or the size of the stereoscopic image 90 is compressed in advance so as to be accommodated in the display size of the display device. Here, the “size” of the image means the number of pixels constituting the image. The size of the image can be expressed as Wx×Wy where Wx designates the number of pixels in a horizontal direction of the image and Wy designates the number of pixels in a vertical direction of the image. In addition, the display size of the display device means the number of pixels which can be displayed on the display device. The display size of the display device can be expressed as Hx×Hy where Hx designates the number of pixels in a horizontal direction of the screen and Hy designates the number of pixels in a vertical direction of the screen.
Apart from the aforementioned assumption, assume that the size of the stereoscopic image 90 is larger than the display size of the display device, for example, assume that the size of a stereoscopic image inside the area 91 in FIG. 13 is the same as the size of the display device. In this case, when the area 91 is moved as described above, the parallax of the stereoscopic image displayed on the display device may change suddenly to thereby give a sense of fatigue to the user viewing the stereoscopic image.
A method for reducing a sense of fatigue given to a user when a scene of a stereoscopic image is changed has been disclosed in Patent Literature 1.
In addition, a method for changing a moving part of stereoscopic image from a stereoscopic display mode to a planar display mode during scroll display of the stereoscopic image has been disclosed in Patent Literature 2.